With increasing mobility it is important to provide communication on a high level of quality, like e.g. a high-speed Internet access, particularly to means of travel that are frequently used for business travels. Such means of travel can be e.g. trains, particularly high speed trains such as the French Train a Grande Vitesse (TGV), the German Inter City Express (ICE), the Japanese Bullet Train Shikansen and the like, magnetically levitated trains such as the Transrapid and the like, all movable with speeds up to 400 km/h and above, but also fast driving motorcars and the like. It is also thinkable to provide such communication to airplanes particularly to such airplanes flying at altitudes below 10.000 ft. Those means of travel are further called ‘vehicles’. Furthermore, providing communication to a vehicle means to provide communication to a network or a communication system that is installed in the vehicle itself as well as to passengers and their mobile devices such as laptops and the like traveling with the vehicle.
To provide such communication, wireless networks seem to be practical.
Thereby three different aspects have to be considered:                1. To guarantee a total coverage of the wireless network along a route such a vehicle moves.        2. To guarantee communication on a constant high level of quality at all speeds the vehicle moves.        3. To guarantee an economically justifiable solution.Furthermore, a main criterion in providing wireless communication services such as email and web browsing is, that from the user point of view, the response time must be lower than some seconds.        
To provide such wireless networks basically two technologies are known.
The first technology is WLAN (Wireless Local Area Network) that is also known as Wireless Fidelity (WiFi). The advantage of WLAN is, that it provides communication at all speeds a vehicle moves. To guarantee a total coverage along a route the vehicle moves, so called WLAN hot spots have to be arranged along the route. The drawback of WLAN is that to provide communication to a vehicle, a very high number of WLAN hot spots are required along the route, since the theoretical outdoor range to be covered by WLAN is only about 20 km, assuming a Line of Sight (LoS), wherein the practical useable range is only about 1 to 2 km, i.e. 500 to 1000 m in each direction.
The second technology is WIMAX (Worldwide Interoperability for Microwave ACCess). WIMAX is similar to WLAN in concept, meaning it also permits the carrying of internet packet data, wherein WIMAX has the advantage over WLAN that it provides a higher performance, i.e. it permits usage over much greater distances. Both, WLAN and WIMAX provide broadband communication with data rates beyond 10 Mb/s. WIMAX theoretically provides up to 50 km of linear service area range and allows connectivity between users without a direct line of sight. The practical useable range of WIMAX is about 10 to 20 km, 5 to 10 km in each direction, i.e. 5 to 20 times higher than the WLAN range. The drawback of WIMAX is that for fast moving vehicles communication via WIMAX is impossible due to Doppler shift. Up to now WIMAX can only be used for vehicle speeds up to 120 km/h.
Both technologies mentioned above use terrestrial networks based on optical fiber to connect via a central switch e.g. to the Internet. Regarding WLAN, the advantages of a cheap installation of single WLAN hot spots due to widely spread technology is defeated, since civil engineering costs for laying terrestrial optical fiber in ground are in the range of 10 k/km. By providing WLAN communication to a vehicle, the WLAN hot spots have to be arranged directly along the route because of short range of WLAN coverage. Due to this WLAN communication requires optical fibers along the route, e.g. along a railway track. Regarding WIMAX and considering its higher range, existing terrestrial networks at least partly can be used.
Other known technologies such as solutions based on satellites do not work in tunnels. Due to this they are not considered here.